Engine not turning over - 1970 F100 Custom Sport

Engine, ignition, fuel, cooling, exhaust

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Jbonman
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Engine not turning over - 1970 F100 Custom Sport

Post by Jbonman »

I have a 1970 F100 Custom Sport. It has been working great since I have had it (6 months) until the battery died. I replaced the battery and now the engine won't turn over. It is a slow roll and if I put the gas pedal to the floor it wants to start but never fully turns over. The headlights work and are strong/unflickering. I checked the battery connections to the new battery (they were tight) and I even ended up replacing them. i had the starter tested and it is working. I thought perhaps I shorted or arced the external solenoid so I replaced that but the engine still won't fully turn over. Could it be the gas or fuel line? Looking for any advice on next steps - I am somewhat of a novice but handy. thanks
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by sargentrs »

Had a similar problem with mine. Turned out to be a bad ring terminal crimp on the wire from the alternator to the solenoid. Replaced solenoid twice (common to be bad new out of the box). On the last one the wire broke at the ring terminal, the one on the battery side of the solenoid. Apparently it was hanging on by a strand and taking it loose 3 times in a row broke it. Crimped on a new terminal and she fired right up. Check your connections and especially your battery ground cable at he block too.
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by Ranchero50 »

Neither gas or fuel if it won't crank over. Jump the battery to the control wire for the starter solenoid to bypass the cab wiring (key etc) and see if cranks. If the headlamps don't dim you don't have continuity through the starter and back to the battery. After trying to crank it over for a couple seconds feel the connections and wiring for hot spots.
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Jbonman
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by Jbonman »

I rechecked the ground connections to the engine and starter and they are tight. I put a voltmeter to the battery and am getting 13+. Is there any straightforward way to test the terminals? I'll ty to Jump the battery to the control wire for the starter solenoid to bypass the cab wiring this afternoon and see what happens
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by Jbonman »

Update: I replaced both the ground to the block and the cable from the solenoid to the starter. I can get it to turn over and fire up only when the pedal is pushed to the floor although it is a slow sputtering (not normal idle RPM) and dies the second I let up on the gas. Lots of smoke from the exhaust. Thoughts?
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by cep62 »

Make sure your choke is open , hold it open with a clothes pin.
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by Bill Ramsey »

Sounds to me like it's flooded. Like stuck or cracked float.
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by Jbonman »

update- Fired up and running smooth! Thank you to CEP62, it ended up being that the choke plate was stuck and not opening properly. A valuable lesson learned and will be incorporated in future troubleshooting steps. Thank you to all for your help and advice!
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Re: Engine not turning over - 1970 F100 Custom Sport

Post by cep62 »

You should check your oil , make sure it's not diluted with gas .(over filled)
Excessive flooding / running rich can cause it to happen.
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